Bowling ball



H. J. LUTH El' AL BOWLING BALL Filed Nov. 25, 1940 Aug. 4, 1942,

Patented Aug. 4, 1942 BOWLING BALL Harold J. Luth,

Muskegon Heights, and Herman B. Scheidemantel, Muskegon, Mich.,assignors to The Brunswick-Balke-Collender Company, Chicago, Ill., acorporation of Delaware Application November 25, 1940, SerialNo.'367,044

9 Claims.

This invention relates to a bowling ball structure designed to combinelight weight and reasonable accuracy of balance.

One object of the invention is to provide a bowling ball in which thecenter of gravity of the core is eccentric with respect to the exterioroutline of the ball in order to offset the absence of material at theusual finger-holes and thus maintain the ball substantially in balance.

Another object of the invention is to provide a bowling ball having anouter shell of material adapted to take a smooth, hard nish, and a coreor filler of material of relatively low specific gravity as comparedwith the shell, together with means included within the shell tending tocompensate for the absence of material in the usual finger-hole or holesso as to maintain the ball in correct balance.

A further object of the invention is to provide a bowling ball composedessentially of hard rubber but having an outer shell presenting a smoothouter surface and having a core of porous hard rubber, together with aprovision to offset the absence of material at the finger-holes of theball.

More specifically, it is an object of the invention to provide a bowlingball composed entirely of hard rubber but having different portions ofdifferent specific gravities and including an outer shell or cover ofcomparatively rich, unloaded rubber stock and a core composed mainly ofsponge or cellular stock but including a portion of more dense material,such as a hard rubber loaded with mineral ller, in which the nger-holesare located. Other objects and advantages will appear from. thefollowing description taken in conjunction with the drawing in which:

Figure 1 is a diametral sectional View of a bowling ball made inaccordance with this invention.

Figures 2, 3 and 4 are diametral sectional views each showing adifferent modification of the invention.

Figure 5 is a diametral section showing a further modification in whichthe core of the ball is composed mainly of light-weight material inspherical form, with a channel formed in the sphere and occupied rial.

Figure 6 is a transverse diametral section taken as indicated at line6-6 on Figure 5.

Figure 7 is a diametral section of an additional modification in which aspherical core of lightby a ring of heavier mateweight material iseccentrically located within a spherical core of heavier material.

While we have shown in the drawing, and shall herein describe in detailcertain preferred forms of our invention as embodied in a bowling ball,it is to be understood that we do not intend to limit the invention tothe specific forms disclosed, but aim to cover all modifications andalternative constructions falling within the spirit and scope of theinvention, as expressed in the appended claims.

Bowling balls have been constructed of various y materials, and therehave been some attempts to employ constructions or designs which wouldresult in a comparatively light-weight ball 4better adapted for use bywomen and young people than the heavier ball regularly employed. Whenthe ball is composed of hard rubber the cover or shell is preferablycomposed of a rich, hard rubber stock of fairly low specific gravity,made up of crude rubber, hard rubber dust and the necessary chemicalsfor vucanization. This produces a stock having satisfactory tensilestrength and elongation, and thus affording the necessary resiliency foruse in a bowling ball and presenting a surface adapted to take a smooth,hard finish. For the core of the ball, however, a composition of higherspecific gravity is frequently employed in which fillers, such as clay,alba Whiting, and the like, may be added to the usual ingredients of thehard rubber stock to reduce the cost. But this core stock, having a highspecific gravity in itself, may be greatly lightened by mixing with thecomposition in plastic form a material which breaks down chemicallyunder the influence of heat employed in curing the rubber, and gives offa gas which permeates the mass so as to produce a honey-combed orcellular formation similar to that of so-called sponge rubber, exceptthat for the purpose of a bowling ball the sponge is hardened by thecuring process. Sodium bicarbonate is frequently Vemployed for thispurpose, and the method of securing this type of rubber, either in theelastic stage or in the hardened form, is generally understood by thoseskilled in the art.

Thus, to produce a ball of lighter weight than would result from Using asolid core of loaded stock, it is only necessary to substitute for allor a part of this core a quantity of hard rubber of the honey-combed orcellular structure. However, when this is done, it is found that theflnger-holes customarily formed in one side of the ball will extend intothis core, and that their surfaces will be rough and broken by reason ofthe core and affords the` ringer-holes 4, 4

the porous formation of the hard rubber core.

Furthermore, the formation of the nger-holes tends to unbalance the ballby reason of the total absence of material at the ringer-holes.

, Both of these disadvantages are overcome by the present inventionwhich provides a ball hav- -ing an outer shell or cover of hard,smooth-surfaced material such as the unloaded rubber composition justmentioned, with a porous or cellular core cured to a suitable degree ofhardness, but with its center of gravity eccentrically located withinthe spherical shell and supplemented by a quantity of heavier core stockpositioned to provide smooth walls for the finger-holes. The higherspecific gravity of the latter material serves lto ofi'set the absenceof material at the linger-A `it may be machined, if necessary, to bringit to substantially accurate form. It is then re-cured with an outerwall of cover stock to form a hard, smooth shell approximatelyve-eighths of an inch thick. The finger-holes are then bored in theportion of the ball which includes the more dense core material, andwhen this operation has been completed the ball is left in substantiallycorrect balance.

Various designs or arrangement may be employed for distributing thelighter and heavier core stocks. Figure l cover I which is nearlyrepresents a ball having a lled with a light-weight core 2,cross-hatched to represent conventionally a cellular formation. Theportion 2 is mainly spherical but has a pocket formed at one side whichis occupied by a quantity of heavier core stockt which completes thespherical form of a suitable material in which may be formed. Figure 2likewise shows a combination of light and heavy materials forming thecore, but in this case the partially spherical light-weight core 5, ofcellular formation, is entirely surrounded by a layer oi' heavier stock8 The formation of a pocket I at one side of the light-weight core 5requires that the heavy stock i be thicker in this vicinity, and thelinger-holes 4, 4 areformed in this thicker portion of the densermaterial.

Figure 3 illustrates an arrangement quite similar to that of Figure 2,except that the lightweight inner core 8 of porous or cellular formationis formed with a at faceat 9 so that the encompassing material I0 ofheavier core stock iills in the space between this nat face 9 and theinner surface of the cover I, providing a thicker portion of the heaviercore material in which the linger-holes 4, 4 are formed.

Figure 4 shows the interior oi.' a lighter weight ball in which a largerportion of` thecore consists of the cellular or sponge stock II. In thiscase the light-weight core nearly lls the cover I and nts against theinner surface of the cover, except at one side. Here the portion I I isformed with a fiat face I2 and a correspondingly shaped section I3 ofheavier core stock ills the space between the cover I and the flatsurface I2. The ilnger-holes 4, 4 are shown located in this heavierportion of the core.

It will -be noted that in each of these stmotures the center of gravityof the light-weight the said finger-hole porous core material at 2, l, lor II will be located eccentrically with respect to the center of theball and at the'opposite side of the center from that at which thefinger-holes are disthe light-weight porof course, that the quantity andeccentricity of the light-weight portion is correctly calculated.

Figures 5 and 8 illustrate a further modincation in which thelight-weight cellular core I4 is marie of substantially spherical formdimensioned to just fill the cover I, but with the channel I5encompassing this spherical core I4 and of a heavier stock I6. Al-

with respect to the center of the ball, as clearly shown in Figure 6.The ring I6 of heavier stock which illls the channel is thusconsiderably thicker at one side than at the other side, and thefinger-holes 4 are located in this thicker portion of the ring so thatthe absence of material at the finger-holes oi!- sets the extra depth ofthe ring at this side and results in a substantially balanced structure. It may be noted that this typeof construction is better suited tothe style of ball having one or two ringer-holes, whereas the otherforms herein shown maybe easily arranged to accommodate threefinger-holes.

In some cases, instead of lightening the core stock by making it porousor cellular in structure, a compositev stock may be employed, consistingof a mixture of cork and rubber. Figure 7 illustrates a furthermoditlcation in the interior design of a bowling ball, and incidentallyshows the light-weight material at II as a ccmpositionof this nature.This light-weight core may be understood as spherical, but is locatedeccentrically of the center of the ball so as to offset the absence ofmaterial at the ilnger-holes, 4, 4. A heavier stock, indicated at Il,completely surrounds the inner light-weight core I1 and combines with itto illl the space inside the cover I. l

We claim as our invention:

1. A bowling ball comprising an outer shell of hard, smooth-surfacedmaterial with a fingerhole placed in the ball atone side, a corecomposed principally of light-weight material mainly spherical in formbut having a flat face disposed in a plane at the same side of thecenter of the ball as said finger-hole, with material of greaterspecific gravity completing the spherical form of the core between saidfiat face and the outer shell, the linger-hole extending into saidheavier material.

2. A bowling ball comprising an outer shell of hard, smooth-` acedmaterial with a ringerhole placed in the ballat one side, a corecomposed principally of light-weight material oi' spherical form with acircumferentially disposed channel, and a ring of greater density thanthe spherical portion illling said channel, the inner circumference ofthe channel and of the ring being eccentric to the center of the sphere,and extending into the thicker portion of said ring.

3. A bowling ball comprising an outer shell of hard rubber and ofuniform thickness and a core composed largely o f hard sponge rubberwith a finger-hole placed in the ball at one side and extending into thecore, the sponge rubber portion of the core being of generally sphericalshape but with a portion of the sphere omitted and linger-holes,providing,

said portion being iilled with hard rubber into which the finger-holeextends, said hard rubber being of greater density than the spongerubber and providing a substantially smooth surface for the iinger-hole.

4. A bowling ball comprising an outer shell oi hard rubber and a core ofhard sponge rubber with a nger-hole placed in the ball at one side andextending into the core, and means forming the wall of the finger-holecomposed of material having a greater specific gravity than the spongerubber of the core, the weight of said means being substantiallysuilicient to compensate for the absence of material in the iinger-hole.

5. A light-weight bowling ball consisting of an outer shell of hardenedplastic material having a smooth external surface and a two-part core inwhich one part is made of a hardened cellular plastic material ofrelatively low speciiic gravity, and the remainder is composed of arelatively dense, hardened plastic material with ailngerhole in one sideof the ball extending into said dense portion of the core, the greaterdensity of said portion compensating for the absence of material in thefinger-hole in maintaining the ball in balance, said shell and the partsof the core being all molded together in a unitary structure.

6. A light-weight bowling ball consisting of an outer shell of hard,smooth-surfaced material and a two-part core in which one part is madeof a hard, cellular material and the remainder is composed of arelatively more dense material, the ball having a nger-hole extendingthrough the shell into the more dense material of the core whereby saidmaterial provides a substantially smooth surface for the finger-hole.

'7. A light-weight bowlingball consisting of an outer shell of hardened,plastic material having a smooth external surface and a two-part corecomposed of a portion of light-weight material having its center ofgravity located eccentrically within the shell and a quantity ofrelatively dense, hardened plastic material encircling the lightweightmaterial and filling the remainder of the space in the shell, said ballhaving a. finger-hole extending through the shell at one side and intosaid dense material of the core, said shell and the two parts of thecore constituting the entire structure of the ball.

8. A light-weight bowling ball in which a portion of the body of theball is made of relatively hard, dense material with a finger-holecontained therein at one side of the ball and the remainder consists ofa core of light-Weight material disposed with its own center of gravityeccentrically located in the ball and at the side of the center thereofopposite that at which the finger-hole is located.

9. A light-weight bowling ball consisting of an outer shell of hard,smooth-surfaced material with a finger-hole placed in the ball at oneside and a core composed principally of light-weight plastic materialgenerally spherical in form and concentric with the shell but with aportion oi the spherical form omitted adjacent the fingerhole, and asingle unitary plastic material of greater specific gravity completingsaid spherical form of the core around the finger-hole.

HAROLD J. LUTH. HERMAN B, SCHEIDEMAN'I'EL.

